It is known in motor vehicles to provide a driver's side air bag module. The module typically includes a base plate and an air bag and inflator fastened to the base plate. It is also known to provide a unitary cover assembly to cover the air bag, inflator, and base plate. The cover assembly is made as a separate component and then is stretched out over the air bag and inflator for attachment to the base plate.
The cover assembly is made by providing a container and curing a foam covering on the outer surface of the container. The cover assembly includes weakened portions defined therein to permit deployment of the air bag. The cover assembly also must include slots at the comers to permit the walls to be spread apart when pulling the cover assembly over the air bag, and base plate during assembly. The container includes a plurality of inwardly tamed container flanges which are fastened to the base plate. It is difficult during the molding process to keep the foam off the flanges for later attachment to the base plate. The air bag, inflator, and cover assembly are each attached to the base plate by fasteners to provide the air bag module. The module with the cover assembly thereon is then suitably mounted to the steering wheel of a vehicle.
This prior art cover assembly has the shortcoming of being a separate piece from the steering wheel. Thus, the prior art must match the color and gloss of the cover assembly with the steering wheel. In addition, the cover assembly is difficult to pull over and assemble to the air bag and base plate. The walls of the cover assembly including both the container and the outer foam must include the corner slots so that it can be bent and spread out to get over the air bag and come back to shape for attachment to the base plate. Sometimes the foam surface is marred during the assembly process and the cover assembly must be scrapped.
It is also known to provide a container which is attached to a one-piece integral steering wheel prior to continuously molding an outer material over the container and steering wheel. The container must be fastened to the steering wheel so that the container does not release from the steering wheel when the air bag deploys. Also, the container must be securely positioned for molding of the outer material. In the prior art, the cover is typically attached to the steering wheel by a plurality of fasteners which adds time and cost to the assembly process.